The present invention relates generally to the structure of a homokinetic universal joint and more particularly to a joint wherein an inner joint member and an outer joint member are engaged for torque transmission therebetween by roller bodies which comprise essentially spherical balls. The roller bodies are engaged within grooves formed on the inner wall of the outer joint member and recesses formed on the inner joint member, with a corresponding number of grooves and recesses being provided.
Furthermore, the invention relates to an assembly wherein there is provided at the center of the joint a guide member supported in the inner joint member for mounting the roller bodies in the bisecting plane of the assembly.
Joint assemblies known in the prior art, for example U.S. Pat. No. 1,847,677, have been found to be uneconomical to manufacture and rather expensive to produce because of cumbersome design characteristics. In such prior art devices, the outer member consists of two parts and a separation must be provided inasmuch as the spherical inner joint member must be enclosed. However, since grooves for retaining the torque transmitting balls extend concentrically to the center of the joint, the separation which must be provided extends through the grooves for the balls. This results in the requirement that the ball grooves of both parts of the joint must be manufactured with very exacting standards in order to ensure a precise shape for the grooves. Moreover, because of the fact that the inner joint member is guided in a hollow space of the outer guide member, a joint of this type will involve large friction surfaces. Additionally, it can only be constructed as a fixed joint. The use of the guide element of such a joint is also uneconomical. For this purpose, the inner joint member must have continuous grooves into which the individual guide elements are placed in order to be subsequently centered by means of a spring element. The grooves receiving the guide elements in the joint member have a very complicated shape and therefore they must be manufactured under very difficult conditions.
Moreover, joints are known, for example from U.S. Pat. No. 2,462,700, which do consist of two joint halves and which are provided with a central control lever. However, guidance of the roller bodies in the bisecting plane of the joint is very difficult and can only be effected by means of additional guide members. Also, in this joint, the first joint member is encircled by the second joint member so that, again, only a fixed joint can be provided. Moreover, in the design of the joint members, only roller bodies which are capable of being supported by pins may be used.
In view of the foregoing, the present invention is directed toward provision of a homokinetic universal joint having a design which is relatively simple and wherein a control member may be provided having long, symmetrical staggered portions for reducing friction losses in a manner whereby the structural length of the joint does not become larger.